Head

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This article is about heads in general. For the heads of humans, see Human head. For other uses, see Head (disambiguation).

Head
The head of a meerkat
Details
Identifiers
Latincaput
TA98A01.1.00.001
TA298
FMA7154
Anatomical terminology

A head is the part of an

smell, and taste. Some very simple animals may not have a head, but many bilaterally symmetric forms
do, regardless of size.

Heads develop in animals by an

anterior
region, forming structures responsible for information processing. Through biological evolution, sense organs and feeding structures also concentrate into the anterior region; these collectively form the head.

The head of a death mask

Human head

Main articles: Human head and Head and neck anatomy

The

cranium (upper portion of the skull that houses the brain). [clarification needed ( The skull can also be described as being composed of the cranium, [1][2]
)]

Sculptures of human heads are generally based on a

cheekbone. Though the number of muscles making up the face is generally consistent between sculptures, the shape of the muscles varies widely based on the function, development, and expressions reflected on the faces of the subjects.[3]

Proponents of identism believe that the mind is identical to the brain. Philosopher John Searle asserts his identist beliefs, stating "the brain is the only thing in the human head". Similarly, Dr. Henry Bennet-Clark has stated that the head encloses billions of "miniagents and microagents (with no single Boss)".[4]

Other animals

The evolution of a head is associated with the cephalization that occurred in Bilateria some 555 million years ago.

Arthropods

Main article: Cephalon (arthropod head)

In some arthropods, especially trilobites, the cephalon, or cephalic region, is the region of the head which is a collective of "fused segments".[5]

Insects

Head of a Nomada-species bee

A typical insect head is composed of eyes,

ocelli (single faceted organs).[6]

Antennae on the insect's head is found in the form of segmented attachments, in pairs, that are usually located between the eyes. These are in varying shapes and sizes, in the form of filaments or in different enlarged or clubbed form.[6]

Insects have mouth parts in various shapes depending on their feeding habits.

hypopharynx which is usually located between the maxillac.[6]

Vertebrates and the "new head hypothesis"

Though invertebrate chordates – such as the tunicate larvae or the lancelets – have heads, there has been a question of how the vertebrate head, characterized by a bony skull clearly separated from the main body, might have evolved from the head structures of these animals.[7]

According to Hyman (1979), the evolution of the head in the

vertebrates has occurred by the fusion of a fixed number of anterior segments, in the same manner as in other "heteronomously segmented animals". In some cases, segments or a portion of the segments disappear. The head segments also lose most of their systems, except for the nervous system. With the progressive development of cephalization, "the head incorporates more and more of the adjacent segments into its structure, so that in general it may be said that the higher the degree of cephalization the greater is the number of segments composing the head".[8]

In the 1980s, the "new head hypothesis" was proposed, suggesting that the vertebrate head is an evolutionary novelty resulting from the emergence of

placodes.[9][10] In 2014, a transient larva tissue of the lancelet was found to be virtually indistinguishable from the neural crest-derived cartilage which forms the vertebrate skull, suggesting that persistence of this tissue and expansion into the entire headspace could be a viable evolutionary route to formation of the vertebrate head.[7]

In society and culture

Heraldry

The flag of Corsica displays a head in profile view
Main article: Heads in heraldry

The heads of humans and other animals are commonly recurring charges in heraldry.[11] Heads of humans are sometimes blazoned simply as a "man's head", but are far more frequently described in greater detail, either characteristic of a particular race or nationality (such as Moors' heads, Saxons' heads, Egyptians' heads or Turks' heads), or specifically identified (such as the head of Moses in the crest of Hilton, or the head of St. John the Baptist in the crest of the London Company of Tallowchandlers).[11][12] Several varieties of women's heads also occur, including maidens' heads (often couped under the bust, with hair disheveled), ladies' heads, nuns' heads (often veiled), and occasionally queens' heads. The arms of Devaney of Norfolk include "three nun's heads veiled couped at the shoulders proper," and the bust of a queen occurs in the arms of Queenborough, Kent.[11] Infants' or children's heads are often couped at the shoulders with a snake wrapped around the neck (e.g. "Argent, a boy's head proper, crined or, couped below the shoulders, vested gules, tarnished gold," in the arms of Boyman).[11]

Art

Study on the proportions of head and eyes by Leonardo da Vinci
"Head of a young man" – Domenico Beccafumi

One of the ways of drawing sketches of heads—as Jack Hamm advises—is to develop it in six well-defined steps, starting with the shape of the head in the shape of an egg. The female head, in particular, is sketched in a double circle design procedure with proportions considered as an ideal of a female head. In the first circle, the division is made of five sections on the diameter, each section of five eyes width. It is then developed over a series of ten defined steps, with the smaller circle imposed partially over the larger circle at the lower end at the fourth stage. Eyes and chins are fitted in various shapes to form the head.[13]

Leonardo da Vinci, considered one of the world's greatest artists, drew sketches of human anatomy using grid structures. His image of the face drawn on the grid structure principle is in perfect proportion.[14] In this genre, using the technique of pen and ink, Leonardo created a sketch which is a "Study on the proportions of head and eyes" (pictured).

Idiomatic expressions

An idiom is a phrase or a fixed expression that has a figurative, or sometimes literal, meaning.

Engineering and scientific fields

The head's function and appearance play an analogous role in the etymology of many technical terms. Cylinder head, pothead, and weatherhead are three such examples.

Gallery

See also

References

  1. ^ which encloses the cranial cavity, and the facial skeleton (includes the mandible). There are eight bones in the cranium and fourteen in the facial skeleton.
  2. ISBN 978-81-906566-4-1
    .
  3. ISBN 978-0-486-22960-7
    .
  4. ISBN 978-0-8028-4837-6
    .
  5. ISBN 978-0-19-957112-3
    .
  6. ^
    ISBN 978-0-86720-017-1
    .
  7. ^
    S2CID 4449267. For lay summary see: "Evolution: How vertebrates got a head". Research. Nature
    (paper). 516 (7530): 171. 11 December 2014.
  8. ISBN 978-0-226-87013-7
    .
  9. S2CID 39290007
    .
  10. PMID 25903628
    .
  11. ^ a b c d "H". Head. heraldsnet.org.
  12. ISBN 978-1-60239-001-0
    .
  13. ISBN 978-0-399-50791-5
    .
  14. ^ "Leonardo da Vinci Face facts". royalcollection.org.
  15. ISBN 978-1-59526-334-6
    .
  16. ISBN 978-0-313-31436-0
    .
  17. ISBN 978-981-09-5822-0
    .
  18. ISBN 978-0-547-67753-8
    .
  19. ISBN 978-0-544-18890-7
    .
  20. TheFreeDictionary.com
    .
  21. ISBN 978-0-19-954378-6
    .
  22. ISBN 978-1-85326-309-5
    .
  23. ^ "English Idioms & Idiomatic Expressions – Body idioms/Head". Learn English Today. 2015. Retrieved 14 September 2015.

Further reading

Wikimedia Commons has media related to Heads.
Look up head or cephalic in Wiktionary, the free dictionary.
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